Previously, a color-unevenness inspection and luminance-unevenness inspection in a mass-production process for a display unit that uses a cathode ray tube (CRT), a liquid crystal display (LCD), or the like capable of displaying a color picture, has been mainly performed with use of a sensory test based on a comparison with a boundary sample. This technique is carried out such that a display screen of the display unit as an inspection target is directly viewed by human being and therefore, this is an inspection close to actual use and also a simple and easy technique.
However, this technique relies largely upon the capabilities of individual inspectors, and thus quality of inspection varies depending on factors such as variations among the individual inspectors and the inspector's degree of fatigue. Therefore, it is difficult to perform a stable inspection.
Under the circumstances, there have been proposed some techniques of objective unevenness inspection without depending on the capability of the inspector (for example, PTLs 1 to 5 and NPLs 1 to 3).